This invention relates to a hydrolyzable resin for use as a vehicle resin of antifouling paints as well as antifouling paints containing said resin.
Antifouling paints containing as a vehicle resin a trialkyltin-containing polymer are known. These resins are advantageous in controlling the release of antifouling agent to a minimum level sufficient to maintain desired antifouling effect at a constant level for a long period of time. In application, the vehicle resin consisting of a trialkyltin-containing polymer is hydrolyzed by the action of weakly alkaline sea water to release the trialkyltin, and at the same time the resin becomes water-soluble so that the paint film is consumed and smoothed. This contributes to the reduction of the frictional resistance of ships against water and, therefore, to the reduction of fuel cost.
The vehicle resins of this type of paints, known as "self-polishing paints", typically consist of copolymers of trialkyltin (meth)acrylate. However, strong concern about the toxic effect of trialkyltin on the ecological system has led to a demand for a new vehicle resin of self-polishing antifouling paints which may replace the trialkyltin-containing polymers.
Most of vehicle resins for self-polishing paints known in the prior art release a metal compound or ion. Recently we have found that some aldehyde compounds such as benzaldehyde or derivatives thereof exhibit an antifouling activity on a variety of aquatic organisms adhering to ships.
It is, therefore, a principal object of the invention to provide a new type of vehicle resins for use in antifouling paint which release upon hydrolysis an antifouling aldehyde in a controlled manner while the remaining hydrolyzed resin is gradually consumed by dissolving in water.